Conventionally, in an image forming apparatus such as a laser printer or a copying machine, there has been used a fixing device to melt and fix a toner image formed on the surface of a sheet with toner. Such a fixing device is provided with a heating roller having a halogen heater as a heating member arranged in the interior thereof and a pressure roller pressed against that heating roller.
Heat of such a heating roller is lost by sheets, and nonuniformity occurs in the surface temperature, resulting in a factor of fixing nonuniformity. Under such a circumstance, to uniform the surface temperature of the heating roller, there are known rollers whose entire surface is provided with a surface layer mixed with carbon nanotubes (for example, refer to Unexamined Japanese Patent Application Publication No. 2007-304374). That surface layer is a composite of a mixture of a fluorine resin as a base material and carbon nanotubes or carbon nanofibers as filler.
As another heating roller, known is a heating roller provided with a coating layer on the roller surface in which carbon nanotubes are dispersed and blended so that the longitudinal directions thereof is arranged in the radius direction of the roller (for example, refer to Unexamined Japanese Patent Application Publication No. 2008-180965).